A team of scientists with cutting edge technology has traveled from Washington to an isolated, fortress-like monastery in the middle of the Sinai Desert that is the home of the oldest continuously operating library on the planet.

They are there to turn their high definition cameras on the monastery’s rare and priceless ancient manuscripts. The ancient animal-skin parchments have been scraped so the earlier texts can be erased and new texts can be written on the old skin. Such erased texts are known as palimpsests. I had seen the word before, but never known the meaning.

In 1999 a policy director from the National Reconnaissance Office which designs spy satellites and imaging systems read about a project at the Walters Art Museum. An anonymous bidder had paid $2 million at auction for a prayer book handwritten in Europe in 1229. The value came from what the prayers had overwritten: 10th century copies of key works by the Greek mathematician Archimedes. They knew there was a hidden text, but they couldn’t read much of it. It has been a ten year project of photographing pages with special lights and filters, and computerized enhancement to discover the lost words.

The monastery has existed in a valley at the base of Mount Horeb since at least the 4th century. In the 6th century, the Emperor Justinian I called for the construction of a monastery at the site of what is to believed to be the biblical Mount Sinai, where the burning bush from which God spoke to Moses rested. The monks preserve their ancient traditions, they have just added some iPads and PowerBooks.

The monastery holds at least 130 palimpsests, all from medieval times. The main enemies to document preservation are mold and insects, but humidity in the desert is so low neither is an issue. There are months or even years between rainstorms, and no rats to chew pages. The library’s isolation has added to the preservation of the documents.